In this paper, we demonstrate that nanoscale membrane electrode assemblies, functioning in a H 2/O 2 fuel cell, can be fabricated by impregnation of anodic alumina porous membranes with Nafion® and phosphotungstic acid. Porous anodic alumina is potentially a promising material for thin-film micro power sources because of its ability to be manipulated in micro-machining operations. Alumina membranes (Whatman, 50 μm thick, and pore diameters of 200 nm) impregnated with the proton conductor were characterized by means of scanning electron microscopy, X-ray diffraction, and thermal analysis. The electrochemical characterization of the membrane electrode assemblies was carried out by recording the polarization curves of a hydrogen-oxygen 5 cm 2 fuel cell working at low temperatures (25∈÷∈80 °C) in humid atmosphere. Our assemblies realized with alumina membranes filled with phosphotungstic acid and Nafion® reach respectively the peak powers of 20 and 4 mW/cm 2 at room temperature using hydrogen and oxygen as fuel and oxidizer